1. Which structure is responsible for radial conduction in stem? A. Vascular bundles B. Cambium C. Medullary rays D. Cortex
2. Which pigment protects chlorophyll from photo-oxidation? A. Chlorophyll b B. Carotenoids C. Phycobilins D. Anthocyanin
3. In dorsiventral (dicot) leaves, stomata are more abundant on: A. Upper epidermis B. Lower epidermis C. Both equally D. Absent in both
4. Photosynthetic rate is highest in: A. Red light B. Green light C. Blue and red light D. Yellow light
5. Annual rings are clearly visible due to difference between: A. Sapwood and heartwood B. Spring wood and autumn wood C. Xylem and phloem D. Primary and secondary xylem
6. RuBisCO shows oxygenase activity when: A. CO₂ concentration is high B. O₂ concentration is low C. CO₂ concentration is low D. Light is absent
10. If light reaction stops but Calvin cycle enzymes remain active, immediate effect is lack of: A. CO₂ B. RuBP C. ATP and NADPH D. Oxygen
12. Emerson enhancement effect demonstrates: A. Two photosystems work together B. Only PS I is functional C. Only PS II is functional D. Photosynthesis doesn't need light
13. Which structure prevents backflow of water into cortex from stele? A. Pericycle B. Endodermis C. Cambium D. Pith
14. Which factor directly reduces photorespiration? A. High temperature B. High O₂ concentration C. High CO₂ concentration D. Low light intensity
15. Stomatal opening during daytime is favoured by: A. Low K⁺ concentration B. High turgidity of guard cells C. Loss of water from guard cells D. Absence of light
17. Which stage of respiration produces maximum ATP? A. Glycolysis B. Krebs cycle C. ETS D. Fermentation
18. Which part of dicot stem shows secondary growth? A. Epidermis B. Vascular bundles C. Cortex only D. Pith
19. Which tissue provides mechanical strength to growing parts of plant? A. Sclerenchyma B. Parenchyma C. Collenchyma D. Xylem
20. Which of the following cells in xylem are living at maturity? A. Tracheids B. Vessels C. Xylem parenchyma D. Xylem fibres
23. Which event occurs first during aerobic respiration? A. ETS B. Krebs cycle C. Glycolysis D. Oxidative phosphorylation
24. In C4 plants, the initial fixation of CO₂ occurs in: A. Mesophyll cells B. Bundle sheath cells C. Guard cells D. Epidermal cells
25. Which cell type stores food in phloem? A. Sieve tube B. Companion cell C. Phloem parenchyma D. Phloem fibre
26. Which permanent tissue is involved in food conduction? A. Xylem B. Collenchyma C. Phloem D. Sclerenchyma
27. Removal of ring of bark from stem affects plant because: A. Xylem transport stops B. Phloem transport stops C. Transpiration stops D. Photosynthesis stops
29. Which tissue is absent in vascular bundle of monocot stem? A. Phloem B. Xylem C. Cambium D. Bundle sheath
30. Which tissue replaces epidermis during secondary growth? A. Cortex B. Periderm C. Endodermis D. Pith
31. Which element activates enzymes of respiration? A. Nitrogen B. Potassium C. Calcium D. Phosphorus
32. Which anatomical feature helps C4 plants reduce photorespiration? A. Large stomata B. Thick cuticle C. Kranz anatomy D. Sunken stomata
33. Hypodermis of dicot stem is composed of: A. Parenchyma B. Sclerenchyma C. Collenchyma D. Chlorenchyma
34. Annual rings are formed due to the activity of: A. Apical meristem B. Intercalary meristem C. Vascular cambium D. Cork cambium
35. The Casparian strip is present in the cell walls of: A. Epidermis B. Endodermis C. Pericycle D. Cortex
38. The upward movement of water occurs mainly through: A. Phloem B. Xylem C. Cortex D. Medullary rays
39. Photoperiodism in plants is perceived by: A. Chlorophyll B. Phytochrome C. Carotenoids D. Xanthophyll
40. The term 'assimilatory power' in photosynthesis refers to: A. ATP and NADPH B. Only ATP C. Only NADPH D. Glucose
41. In CAM plants, stomata open: A. During day B. During night C. Throughout the day D. Only in rainy season
42. Monocot stem lacks secondary growth mainly because: A. Vascular bundles are scattered B. Cambium is absent C. Pith is absent D. Hypodermis is sclerenchymatous
43. Which factor directly controls stomatal movement? A. Mesophyll cells B. Epidermal cells C. Guard cells D. Cortex
44. Lenticels differ from stomata in that lenticels: A. Are actively regulated B. Occur only on leaves C. Remain permanently open D. Control transpiration efficiently
45. Photosystem II is named so because it: A. Functions after PSI B. Was discovered later C. Functions before PSI D. Produces ATP only
46. Which of the following cells in xylem are living at maturity? A. Tracheids B. Vessels C. Xylem parenchyma D. Xylem fibres
47. Which feature distinguishes dicot stem from monocot stem? A. Presence of epidermis B. Scattered vascular bundles C. Open vascular bundles D. Ground tissue
48. Translocation of organic solutes occurs through: A. Xylem vessels B. Tracheids C. Sieve tubes D. Xylem fibres
49. In the light reaction of photosynthesis, oxygen is released from: A. Carbon dioxide B. Water C. Glucose D. Chlorophyll